06_RA41336EN50GLA1_LTE Mobility Connected Mode

LTE Counters and KPI [RL50] [RL50] RA4133-50A Mobility measurements

Module 6

RA41336EN50GLA1

©2014 Nokia Solutions and Networks. All rights reserved.

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Course Objectives • Mobility measurements • After completing this learning element, the participant should be able to: • • • • • • • • •

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Differentiate HO types and Mobility events in LTE. Describe the intra and inter eNodeB Handover phases and related KPI's. Describe Inter-eNB Inter-Frequency Load Balancing Explain inter-frequency / inter-RAT redirection. Describe HO via X2 interface. Describe HO via S1 interface. Describe Performance matters relating to CSFB. Describe Performance matters relating to SRVCC. Describe the inclusion of the HeNB support.

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Contents 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

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LTE Handover Mobility Architecture Intra eNodeB Handover Inter eNodeB Handover via X2 interface Inter eNodeB Handover via S1 interface Intra-LTE Inter-Frequency Handover Inter-eNB Inter-Frequency Load Balancing Inter-System Mobility SRVCC to WCDMA and GSM X2 Interface Measurements Open Access Home eNB Mobility

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Handover Types LTE • Hard HO in any case, no SHO

• Intra-RAT Handover – Intra eNodeB

– Inter eNodeB  Data forwarding over X2 • High performance for 15…120 km/h • Optimized performance for 0…15 km/h  If no X2 interface configured between serving and target eNodeB, than HO via S1 interface • Inter-RAT

Handover

- PS HO to WCDMA in RL30 - PS HO to GSM not be available, using NACC in RL30

- SRVCC for WCDMA and GSM new in RL40

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Handover Types LTE other RAT intersystem HO

intersystem HO

triggered by other RAT

triggered by e.g. - coverage of E-UMTS - service

E-UTRAN macro cell

- load

Inter frequency HO

E-UTRAN micro cells

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Intra-frequency HO

intra-frequency HO

(intra eNB)

(inter eNB, inter MME) RA41336EN50GLA1


Handover Procedure • -> Lossless

• Packets are forwarded from the source to the target • -> Network-controlled

• Target cell is selected by the network, not by the UE • Handover control in E-UTRAN (not in packet core) • -> UE-assisted • Measurements are made and reported by the UE to the network • -> Late path switch • Only once the handover is successful, is the backhaul tunnel moved

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Handover Procedure Before handover S-GW + P-GW MME

Source eNB

Handover preparation S-GW + PGW MME

Target eNB

S-GW + P-GW MME

Late path switching S-GW + P-GW MME

X2

= Data in radio = Signalling in radio = GTP tunnel = GTP signalling 9

Radio handover

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= S1 signalling = X2 signalling


Handover Algorithm - Initiated by a measurement report - Handover algorithm decides on HO - The Handover procedure is composed of a number of single functions: -

Measurements Filtering of measurements Reporting of measurement results Hard handover algorithm Execution of handover

Inter eNb X2 HO

Intra eNb Inter eNb S1 HO

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Handover Events LTE • Intra-RAT Handover (NSN implementation) - Currently based on RSRP only, but not on RSRQ

- Events for intra-frequency HO - A3: A LTE neighbor becomes better than the server according a relative offset

- A5: The server becomes worse than an absolute threshold and a LTE neighbor better than another absolute threshold

- Events for inter-frequency mobility - A2: The serving cell becomes worse than an absolute threshold (triggers redirection) - A4: Neighbor cell becomes better than a threshold – (Intra eNB Inter freq load balancing)

• Inter-RAT Mobility • Event based inter-RAT handover

• B1- Inter Rat Neighbor is better than a threshold • B2 - Inter Rat Neighbor is better than a threshold and serving cell is below a threshold

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Event A3 RSRP

neighbor a3Offset LNCEL, -30..30 dB, 0 dB

a3TimeToTrigger LNCEL, 0..5120 ms (irregular steps), 0 ms

server

start event A3 reporting

time HO execution

a3ReportInterval LNCEL, 120 ms..60 min (irregular steps), 1024 ms

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Event A5 RSRP neighbor Threshold3a LNCEL, -140..-43 dBm, -140 dBm

server Threshold3 LNCEL, -140..-43 dBm, -140 dBm a5TimeToTrigger LNCEL, 0..5120 ms (irregular steps), 0 ms

start event A5 reporting

time HO execution

a5ReportInterval LNCEL, 120 ms..60 min (irregular steps), 1024 ms 13

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Contents 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

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Intra eNodeB Handover (Positive) Target eNB Source eNB UE RRC Connection Reconfiguration (Measurement Control)

MME

SGW

UL/DL Data (source cell) L2 UL Allocation M8009 Intra eNodeB Handover Measurements On level of source cell

RRC Measurement Reports

Handover decision M8009C1 Total handover decisions

Handover decision Admission control and resources allocation on target cell

Handover preparation M8009C2 Attempted intra eNodeB handover preparations

L2 DL Allocation

Handover Execution M8009C6 Attempted intra eNodeB handovers

L2 Synchronization L2 UL Allocation + timing advance RRC Connection Reconfiguration Complete

Handover completion M8009C7 Successful intra eNodeB handovers

Release source resources

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UL/DL Data RA41336EN50GLA1

(target cell)


Timer THOoverall (hardcoded)

RRC Connection Reconfiguration

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Intra eNodeB Handover (Negative)

UE

Target eNB

Source eNB RRC Measurement Control

MME

UL/DL Data (source cell)

L2 UL Allocation RRC Measurement Reports Handover decision

M8009C0 Total not started HO preparations

M8009C0 updated if the HO decision is not to HO at this time when measurement report has been received from UE 17

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SGW

Intra eNodeB Handover

UE

Source eNB

Target eNB

MME

Which counter is triggered?

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SGW

Intra eNodeB Handover UE

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Source eNB

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Target eNB

MME


SGW


UE

Target eNB


MME



Admission control and resources allocation on target cell

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M8009C3: Failed intra eNodeB HO preparations due to admission control (internal eNB trigger) M8009C5: Failed intra eNodeB HO preparations due to other reason


SGW


UE

Target eNB


MME



Admission control and resources allocation on target cell L2 DL Allocation

M8009C12: Intra eNB HO drops due to RL failure M8009C13: Intra eNB HO drops due to other failure

RRC Connection Reconfiguration

L2 Synchronization missing

M8009C8 Total intra eNodeB HO failures due to timer

RRC Connection Reconfiguration Error or missing 21

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THOoverall expires ©2014 Nokia Solutions and Networks. All rights reserved.

SGW

Mobility Robustness LTE_533 Late handover (M8015C16)

S T RLF in Scell

Early handover type 1 (M8015C17)

RRC Connection re-establishment request in Tcell

Early handover type 2 (M8015C18)

S

S

T

Connection re-establishment request in Scell

T HO fails in T Cell

N

HO “Succeeds” in T Cell

Shortly afterwards - RRC Connection re-establishment request in Ncell

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Intra eNodeB Handover per Neighbor

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•

Counters of group M8009 give information per source cell only

•

Counters of group M8015 give information per neighbor -

M8015C0: Failed intra eNodeB HO preparations

-

M8015C1: Intra eNodeB HO attempts

-

M8015C2: Intra eNodeB HO successes

-

M8015C15: Intra eNodeB HO failures (any reason)

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Intra eNodeB Handover Counter Summary M8009C0



M8009C3/C5

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M8009C1

M8009C2

Positive/negative HO decision

HO preparation attempt RA41336EN50GLA1

M8009C6

M8009C7

Successful/failed Successful HO HO preparation execution ©2014 Nokia Solutions and Networks. All rights reserved.



Intra eNodeB Handover KPIs

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Intra eNodeB Handover KPIs LTE_5036a E-UTRAN HO Preparation Success Ratio (intra eNodeB)

Describes the success ratio for the handover preparation phase The source eNodeB attempts to prepare resources and finally attempts to start the handover to a neighboring cell within the own eNodeB

Logical formula Intra HO prep SR = (number of successful intra eNB HO prep) / (total number of intra eNB HO preparations) * 100% = (number of intra eNB HO attempts) / (total number of intra eNB HO preparations) * 100%

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Summarization formula (PI ID)

Summarization formula (Abbreviation)

100 * sum ([M8009C6]) / sum([M8009C2])

100 * sum ([ATT_INTRA_ENB_HO]) / sum ([INTRA_ENB_HO_PREP])

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Intra eNodeB Handover KPIs LTE_5035a E-UTRAN HO Success Ratio (intra eNodeB)

Describes the success ratio for the handover execution phase The source eNodeB receives information that the UE successfully is connected to the target cell within own eNodeB

Logical formula Intra HO SR = (number of successful intra eNB HOs) / (number of intra eNB HO attempts) * 100%

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100 * sum ([M8009C7]) / sum([M8009C6])

100 * sum ([SUCC_INTRA_ENB_HO]) / sum ([ATT_INTRA_ENB_HO])

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Intra eNodeB Handover KPIs LTE_5040b E-UTRAN HO Failure Ratio (intra eNodeB)

Describes the ratio of failed intra eNodeB handovers related to all attempted intra eNodeB handovers Represents the case of a failed handover when all UE resources are still allocated for the UE

Logical formula Intra HO FR = (number of unsuccessful intra eNB HOs) / (number of intra eNB HO attempts) * 100%

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100 * sum ([M8009C8]) / sum([M8009C6])

100 * sum ([ENB_INTRA_HO_FAIL]) / sum ([ATT_INTRA_ENB_HO])

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Intra eNodeB Handover KPIs LTE_5043a E-UTRAN Total HO Success Ratio (intra eNodeB) Describes the total intra eNB HO Success Ratio from HO preparation start until successful HO execution

Logical formula Intra tot HO SR = (intra eNB HO prep successes) / (intra eNB HO preparations) * (intra eNB HO successes) / (intra eNB HO attempts) * 100% = (intra eNB HO attempts) / (intra eNB HO preparations) * (intra eNB HO successes) / (intra eNB HO attempts) * 100% = (intra eNB HO successes) / (intra eNB HO preparations) * 100%

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100 * sum ([M8009C7]) / sum ([M8009C2])

100 * sum ([SUCC_INTRA_ENB_HO]) / sum ([INTRA_ENB_HO_PREP])

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Intra eNodeB Handover KPIs

1,000

100.00

900 800 700

95.00

600 500 90.00

400 300 85.00

200 100

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LTE_5123a Intra eNB Handover Preparations (#)

LTE_5124a Intra eNB Handover Attempts (#)

LTE_5036a intra eNB Handover Prep Success Ratio (%)

LTE_5035a intra eNB Handover Success Ratio (%)

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Principle • Basic mobility feature • Triggered by same configurable events as intra eNodeB handover • Coverage based (event A5) • Best cell based (event A3)

• Network evaluated handover decision • Data forwarding via X2

• Radio Admission Control (RAC) gives priority to handover related access over other scenarios

S1

X2

S-GW

MME

P-GW S1

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Inter eNodeB Handover (Positive, Preparation) UE

Target eNB


MME

SGW

UL/DL Data (source cell) L2 UL Allocation

M8014 Inter eNodeB Handover Measurements On level of source cell

RRC Measurement Reports Handover decision X2AP Handover Request


Handover preparation M8014C0 Attempted Inter eNodeB handover preparations

X2AP Handover Request Acknowledge Timer TX2RELOCprep (hardcoded) Supervises preparation phase 33

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Inter eNodeB Handover (Positive, Execution)

UE

Source eNB

Target eNB

MME

SGW

X2AP Handover Request Acknowledge L2 DL Allocation RRC Connection Reconfiguration X2AP Status Transfer

Data forwarding

Handover execution M80014C6 Attempted inter eNodeB handovers

L2 Synchronization L2 UL Allocation + timing advance

RRC Connection Reconfiguration Complete Timer TX2RELOCexec (hardcoded) Supervises execution phase 34

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Inter eNodeB Handover (Positive, Completion) UE

Source eNB

Target eNB

MME

SGW

RRC Connection Reconfiguration Complete RRC Connection Reconfiguration (Meas. Reconfig.) Path Switch Request

User Plane Update Request

RRC Connection Reconfiguration Complete

End Marker Packet Data User Plane Update Response Path Switch Request Acknowledge

X2AP UE Context Release

Handover completion M80014C7 Successful inter eNodeB handovers

Release source resources UL/DL Data (target cell) 35

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Inter eNodeB Handover (Negative) UE

Target eNB


MME

SGW

UL/DL Data (source cell) L2 UL Allocation

RRC Measurement Reports Handover decision X2AP Handover Request

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• M8014C2: Failed inter eNodeB HO preparations • due to timer: eg TX2RELOCprep


• M8014C3: Failed inter eNodeB HO preparations • due to target eNodeB admission control

X2AP Handover Preparation Failure or no response

• M8014C5: Failed inter eNodeB HO preparations • due to other reason

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Inter eNodeB Handover (Negative)

UE

Source eNB

Target eNB

MME

SGW

RRC Connection Reconfiguration Complete RRC Connection Reconfiguration (Meas. Reconfig.) Path Switch Request User Plane Update Request

RRC Connection Reconfiguration Complete

End Marker Packet Data Error or no response

M80014C8: Total inter eNodeB HO failures due to timer

Error or no response

TX2RELOCoverall expires

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Inter eNodeB Handover per Neighbor

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•


•


M8015C5: Failed inter eNodeB HO preparations

-

M8015C6: Failed inter eNodeB HO preparations due to timer

-

M8015C7: Failed inter eNodeB HO preparations due to admission control

-

M8015C8: Inter eNodeB HO attempts

-

M8015C9: Inter eNodeB HO successes

-

M8015C10: Inter eNodeB HO failures (any reason)

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Inter eNodeB Handover Counter Summary



M8014C2/C3/C5 M8014C8

M8014C0

M8014C6

HO preparation attempt 39

M8014C7



Successful/failed Successful/failed HO preparation HO execution

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Inter eNodeB Handover KPIs LTE_5049b E-UTRAN HO Preparation Success Ratio (inter eNodeB X2 based)

Describes the success ratio for the handover preparation phase The source eNodeB attempts to prepare resources and finally attempts to start the handover to a neighboring cell in a target eNodeB

Logical formula Inter X2 based HO prep SR = (number of successful inter eNB X2 based HO prep) / (total number of inter eNB X2 based HO preparations) * 100% = (number of inter eNB X2 based HO attempts) / (total number of inter eNB X2 based HO preparations) * 100%

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100 * sum ([M8014C6]) / sum([M8014C0])

100 * sum ([ATT_INTER_ENB_HO]) / sum ([INTER_ENB_HO_PREP])

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Inter eNodeB Handover KPIs LTE_5048b E-UTRAN HO Success Ratio (inter eNodeB X2 based)

Describes the success ratio for the handover execution phase The source eNodeB receives information that the UE successfully is connected to the target cell within target eNodeB

Logical formula Inter X2 based HO SR = (number of successful inter eNB X2 based HOs) / (number of inter eNB X2 based HO attempts) * 100%

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100 * sum ([M8014C7]) / sum([M8014C6])

100 * sum ([SUCC_INTER_ENB_HO]) / sum ([ATT_INTER_ENB_HO])

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Inter eNodeB Handover KPIs LTE_5055b E-UTRAN HO Failure Ratio (inter eNodeB X2 based)

Describes the ratio of failed inter eNodeB X2 based handovers related to all attempted inter eNodeB handovers Represents the case of a failed handover when all UE resources are still allocated for the UE

Logical formula Inter X2 based HO FR = (number of unsuccessful inter eNB X2 based HOs) / (number of inter eNB X2 based HO attempts) * 100%

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100 * sum ([M8014C8]) / sum([M8014C6])

100 * sum ([INTER_ENB_HO_FAIL]) / sum ([ATT_INTER_ENB_HO])

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Inter eNodeB Handover KPIs LTE_5058b E-UTRAN Total HO Success Ratio (inter eNodeB X2 based) Describes the total inter eNB X2 based HO Success Ratio from HO preparation start until successful HO execution

Logical formula Inter tot X2 based HO SR = (inter eNB X2 based HO prep successes) / (inter eNB X2 based HO preparations) * (inter eNB X2 based HO successes) / (inter eNB X2 based HO attempts) * 100% = (inter eNB X2 based HO attempts) / (inter eNB X2 based HO preparations) * (inter eNB X2 based HO successes) / (inter eNB X2 based HO attempts) * 100% = (inter eNB X2 based HO successes) / (inter eNB X2 based HO preparations) * 100%

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100 * sum ([M8014C7]) / sum ([M8014C0])

100 * sum([SUCC_INTER_ENB_HO]) / sum ([INTER_ENB_HO_PREP])

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Inter eNodeB Handover KPIs 12,000 100.00 10,000

95.00

8,000

6,000 90.00

4,000 85.00 2,000

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LTE_5126a Inter eNB Handover Preparations (#)

LTE_5125a Inter eNB Handover Attempts (#)

LTE_5049a inter eNB Handover Prep Success Ratio (%)

LTE_5048a inter eNB Handover Success Ratio (%)

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LTE 54/Intra LTE Inter eNB Handover via S1 Interface

• S1-based handover is only applicable for inter-eNB handover • LTE inter-eNB handover can be executed without X2 interface usage in following scenarios: - No X2 connectivity existing between Source and Target eNB (or blacklisted by operator) - MME or S-GW change required when routing via Core Network • User data traffic and signaling messages are indirectly sent via core nodes (MME and S-GW) • For UE there is no difference whether HO is executed via X2 or S1 interface • Feature has an impact on dimensioning and is taken into account in ANTdim tool

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Inter eNodeB Handover per Neighbor

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•


•


M8014C14: inter eNodeB S1-HO preparations

-

M8014C15: Failed inter eNodeB S1-HO preparations due to timer

-

M8014C16: Failed inter eNodeB S1-HO preparations due to admission control

-

M8014C17: Failed inter eNodeB S1-HO preparations due to other reason

-

M8014C18: Inter eNodeB S1-HO attempts

-

M8014C19: Inter eNodeB S1-HO successes

-

M8014C20: Inter eNodeB S1-HO failures due to timer

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Key phases of handover procedure LTE54 Intra LTE Inter eNB Handover via S1 Interface 1/2 - Key phases:

Execution

Preparation

Logically the message content is created at target eNB and conveyed to Source eNB through MME

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Key phases of handover procedure LTE54 Intra LTE Inter eNB Handover via S1 Interface 2/2

completion

- Key phases:

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Preparation

M8014C14: INTER_ENB_S1_HO_PREP

• M8014C15: Failed inter eNodeB S1 HO preparations due to timer: eg TS1RELOCprep • M8014C16: Failed inter eNodeB S1 HO preparations due to target eNodeB admission control 50

• M8014C17: Failed inter eNodeB S1 HO©2014 preparations due to other reason RA41336EN50GLA1 Nokia Solutions and Networks. All rights reserved.

Key phases of handover procedure LTE54 Intra LTE Inter eNB Handover via S1 Interface - Key phases: Source eNB UE

Target eNB

MME

M8014C18: INTER_ENB_S1_HO_ATT

TS1RELOCOverall

10. Handover Control

9b. Create Indirect Data forwarding Tunnel Response

11. Trigger HO decision 12. RRC Connection Reconf.

Deliver buffered and in transit packets to target eNB 13a. eNB Status Transfer 13b. MME Status Transfer (Indirect) Data forwarding (Indirect) Data forwarding

Buffer Packets from Source eNB 14. Synchronization 14a. UL allocation + TA for UE 15. RRC Connection Reconf. Complete • M8014C20: Failed inter eNodeB S1 due to timer: eg TS1RELOCoverall 51

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SGW



Source eNB

completion

UE

52

Target eNB

MME

M8014C19: INTER_ENB_S1_HO_SUCC

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SGW

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Inter-frequency handover

1 set of counters for 3 scenarios • • •

M8021C2

M8021C0

M8021C4

Attempts

Success

Attempts With Measurement gap

Success With Measurement gap

M8021C1 54

Intra eNB HO inter frequency Inter eNB HO inter frequency via X2 Inter eNB HO inter frequency via s1

M8021C3 RA41336EN50GLA1

Fail

Fail With Measurement gap M8021C5


Inter-frequency handover Inter eNB via X2 counters

UE

Source eNB

Target eNB

MME

SGW

RRC Connection Reconfiguration RRC Connection Reconfiguration Complete Measurement report HO decision

HO_INTERFREQ_ATT (M8021C0) HO_INTFREQ_GAP_ATT (M8021C1)

Handover request Handover request Ack/ HO command RRC Connection Reconfiguration SN Status transfer Synchronisation Random Access RRC Connection Reconfiguration Complete

Path switch request Modify bearer request

HO_INTERFREQ_SUCC (M8021C2) HO_INTFREQ_GAP_SUCC (M8021C3)

Modify bearer response

Path switch request ack UE context release 55

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Inter-frequency handover Inter eNB via X2 counters

UE

Source eNB

Target eNB

MME

SGW

RRC Connection Reconfiguration RRC Connection Reconfiguration Complete Measurement report HO decision Start TX2RELOCoverall

Handover request Handover request Ack/ HO command

RRC Connection Reconfiguration SN Status transfer Synchronisation Random Access RRC Connection Reconfiguration Complete

HO_INTERFREQ_FAIL(M8021C04) HO_INTFREQ_GAP_FAIL (M8021C5)

Path switch request Modify bearer request TX2RELOCoverall Expires due to no context release

Modify bearer response

Path switch request ack

UE context release 56

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Inter-Frequency Handover KPI LTE_5114a E-UTRAN Inter-Frequency HO Success Ratio This KPI describes the success ratio for the inter-frequency HO, when the source eNB receives information that the UE successfully is connected to the target cell within target eNB. The KPI is defined independent of the network topology (intra eNB HO / inter eNB HO) and of the usage of measurement gaps.

Logical formula Inter Frequency HO SR = (number of successful Inter-Frequency HOs) / (number of Inter-Frequency HO attempts)*100%

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100*sum([M8021C2]) / sum([M8021C0])

100*sum(HO_INTFREQ_SUCC]) / sum (HO_INTFREQ_ATT])

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Inter-Frequency Handover KPI LTE_5115a E-UTRAN Inter-Frequency HO Success Ratio Measurement Gap assisted This KPI describes the success ratio for inter-frequency HO when measurement gaps are configured for the UE, when the source eNB receives information that the UE successfully is connected to the target cell within target eNB. The KPI is defined independent of the network topology (intra eNB HO / inter eNB HO).

Logical formula Inter Frequency HO SR = (number of successful Inter-Frequency HOs measurement gap assisted) / (number of Inter-Frequency HO attempts measurement gap assisted)*100%

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100*sum([M8021C3]) / sum([M8021C1])

100*sum(HO_INTFREQ_GAP_SUCC]) / sum (HO_INTFREQ_GAP_ATT])

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Intra-Frequency Handover KPI LTE_5568a E-UTRAN Intra-Frequency HO Success Ratio This KPI describes the success ratio for the intra-frequency HO, when the source eNB receives information that the UE successfully is connected to the target cell. The KPI is defined independent of the network topology (intra eNB HO / inter eNB HO).

Logical formula Intra Frequency HO SR = (number of successful Intra-Frequency HOs) / (number of Intra-Frequency HO attempts)*100%

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100*sum([M8009C7] + [M8014C7] + [M8014C19] [M8021C2]) / sum([M8009C6] + [M8014C6] +[M8014C18] [M8021C0])

100*sum([SUCC_INTRA_ENB_HO] + [SUCC_INTER_ENB_HO] + [INTER_ENB_S1_HO_SUCC] [HO_INTFREQ_SUCC]) / sum([ATT_INTRA_ENB_HO] + [ATT_INTER_ENB_HO] + [INTER_ENB_S1_HO_ATT] [HO_INTFREQ_ATT])

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Inter-eNB Inter-frequency Load balancing RL50 



LTE1170 extends LTE1387 functionality in providing means to move incoming load from a high-loaded cell to low-loaded cells which use different frequency than the high-loaded serving cell

Continuous load Measurement and Exchange Step 1

Load Supervision and Exchange

Step 2

Candidate UE Selection for Measurement Solicitation

Step 3

Measurement Solicitation

The feature balances load only between interfrequency cells

Step 4

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iF-LB Execution


Inter-eNB Inter-frequency Load balancing RL50 Cell in LB mode

100% iFLBHighLoadxxx



Update every 1sec

M8011C69

Rel. LoadX(t)

iFLBTargetLoadxxx @ 60%

100%

ACX(t) 50%

80% 60%

Suppose that actual cell load for load type XXX (DL GBR/DL non-GBR/PDCCH) is as shown

LoadX(t) 30%

High cell load indicator for load balancing

Rel. LoadX(t) 50%

40%

Available capacity in relation to configured target load threshold

20%

50% of the cell’s configured target load threshold for load type X(DL GBR/DL non-GBR/PDCCH) is already being utilized in the cell 62

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Inter-eNB Inter-frequency Load balancing RL50 UE

Source eNB

Target eNB

RRC Connection Reconfiguration (cause load based HO)

M8021C23

Number of load balancing Handover attempts

M8021C24

Number of successful load balancing Handover completions

L2 Synchronization L2 UL Allocation + timing advance

RRC Connection Reconfiguration Complete UE context release

63

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Contents 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

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Event A2 Based Redirection • RL10 does not support inter-frequency / inter-RAT HO, but just redirection based on event A2

• Redirection is triggered, if the coverage of the server is below threshold4 for at least the time given by a2TimeToTriggerRedirect

• Event A2 may be triggered, if e.g. the coverage goes down because no target cell can be found for handover triggered by event A3 or A5 RSRP

server threshold4 LNCEL, -140..-43 dBm a2TimeToTriggerRedirect LNCEL, 0..5120 ms (irregular steps)

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time

©2014 Nokia Solutions and Networks. All rights reserved. start redirection

Event A2 Based Redirection

• Must be enabled with actRedirect (LNBTS, off/on, on) • The number of potential target layers is set with redrtId (REDRT, 1..2) • The type of target layer is set with redirRAT (REDRT, LTE/WCDMA/(E)GPRS), i.e. redirection is possible towards

•

WCDMA

•

GPRS/EDGE

•

Another LTE carrier

• Further parameters are used to specify e.g. the (U)ARFCNs of the target layers • RL10 does not offer detailed counters to monitor redirection • The number of EPS bearer releases due to redirection is given by the counter M8006C15

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CSFB in Pre RL40 release • CS Fallback related features in RL20 • CS Fallback to UTRAN or GSM via Redirect (LTE562) • Emergency Call Handling (LTE22) –

• CS Fallback related features in RL30 • CS Fallback to UTRAN with System Information • CS Fallback related features in RL40 • CS Fallback to UTRAN via PS HO (LTE736) • GSM Redirect with System Information (LTE984) - this enhancement applies also to RRC Connection Release with Redirection (LTE423)

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CS Fallback to UTRAN

RL40 - perform CSFB to UTRAN – PS HO Blind HO is not supported therefore e-NB will trigger measurements before CS Fallback to UTRAN.

Configure B1 event based measurements for UTRAN (3GPP)

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Event B2

measQuantUtraFdd

1. Ms + Hys < Thresh1 & 2. Mn + Ofn – Hys > Thresh2

def. which quantity to use for event B2 LNCEL; cpichRSCP, cpichEcN0; notUsed; cpichRSCP

Signal level

condition 2 fulfilled Event B2 fulfilled condition 1 fulfilled

b2threshold2UtraRscp/EcN0 offsetFreqUtra hysB2ThresholdUtra

S-cell

b2threshold1Utra hysB2ThresholdUtra reportAmount N-cell time

b2TimeToTriggerUtraMeas LNHOW; 0..5120ms; -; 69

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reportIntervalUtra LNHOW; 120ms..60 min; -; -

S – serving cell LTE N – neighbor cell WCDMA


Event B1

measQuantityCSFBUtra

1. Mn + Ofn – Hys > Thresh2

def. which quantity to use for event B1 LNCEL; cpichRSCP, cpichEcN0; notUsed; cpichRSCP

Signal level

Event B1 fulfilled

hysB1ThresholdCSFBUtra b1thresholdCSFBRscp/EcN0

reportAmount N-cell time

b1TimeToTriggerUtraMeas LNHOW; 0..5120ms; -; 70

RA41336EN50GLA1

reportIntervalUtra LNHOW; 120ms..60 min; -; -

S – serving cell LTE N – neighbor cell WCDMA


CS fallback to UTRAN RL40 LTE736 • Possibility to perform CSFB to UTRAN using PS HO functionality • PS HO to WCDMA for FDD • PS HO to WCDMA or TD-SCDMA for TDD • Benefits: • Faster than CSFB via Redirection • PS services are not dropped • Support for MO and MT cases as well as for RRC_IDLE and RRC_CONNECTED states • Emergency Call can use CS Fallback to UTRAN with PS HO

WCDMA

LTE CSFB

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RL40 - perform CSFB to UTRAN – PS HO

LTE736 perform CS Fallback to UTRAN using PS HO functionality  In case of LTE FDD => PS HO to WCDMA is used  appropriate feature activation flag (actCsfbPsHoToUtra) on the eNB level UE

eNB

Paging

MME

Paging

Paging Paging

RRC: RRCConnectionRequest RRC: RRCConnectionSetup RRC: RRCConnectionSetupComplete / Extended Service request Extended Service request S1AP: UE CONTEXT MODIFICATION REQUES with the CS Fallback Indicator or S1AP: INITIAL CONTEXT SETUP REQUEST with the CS Fallback Indicator

RRC: RRCConnectionRelease message

(CSFB_PSHO_UTRAN_ATT) M8016C32 72

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M8016C11 M8016C12 M8016C13 M8000C31 M8016C32

73

CS Fallback attempts with redirection via RRC Connection Release CS Fallback attempts (UE in Connected Mode) with redirection via RRC Connection Release CS Fallback attempts for emergency call reason with redirection via RRC Connection Release UE Context modification attempts due to CS Fallback CS Fallback attempts to UTRAN with PS Handover

RA41336EN50GLA1


CS Fallback Statistics (MT RRC_Connected)

Which counters are triggered? What is the cause of the release?

74

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CS Fallback Statistics (MT RRC_Connected)

75

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Contents 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

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SRVCC to WCDMA (LTE 872) Introduction  The aim of the LTE872 feature is to command the UE to leave LTE network if the LTE coverage is ending and handover the VoIP call (QCI = 1) to the WCDMA network via Single Radio Voice Call Continuity procedure – in the IMS capable environment

 SRVCC functionality is standardized by the 3GPP and the idea behind this feature is to handover ongoing VoIP call from LTE to another RAT with simultaneous change of the domain that serves the connection – from PS to legacy CS

 Feature prerequisite is 3G capability of the LTE UE  Prior to the actual SRVCC procedure the measurements of 3G network are triggered

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SRVCC to GSM (LTE 873) Variants of SRVCC to GSM  Following variants of SRVCC are supported by LTE RL40/RL35TD:  SRVCC to GSM without DTM support  VoIP connection is handed over to GSM CS but other PS bearers are suspended and they could be resumed only after performing Routing Area Update – after the CS call end

 Special option: Emergency SRVCC to GSM without DTM support  SRVCC to GSM with DTM support  VoIP connection is handed over to GSM CS, other PS bearers are not handed over but these PS bearers are established again after performing Routing Area Update – during the CS call (with the help of DTM mode)

 Special option: Emergency SRVCC to GSM with DTM support

PS handover to GSM is in any case not supported – with or without SRVCC to GSM functionality

78

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SRVCC to WCDMA (LTE872)

CS Access and Call Control

CS Bearer

CS-MGW

2G/3G

SRVCC enhanced MSS IU-CS / A

UE

Originating services & anchoring

SRVCC

UTRAN/G ERAN

HLR

MAP

Sv

SRVCC

LTE Access with IMS Call Control

MGCF

IMS-MGW

NVS

HSS

MME

UE S1-MME

PCRF

STa S11

S6b

Cx

SCC ASCC ISC

Rx

Gx Gm

S1-U

Mw

CSCF SGi (VoIP Bearer)

UE

79

eNb

Signaling CS Bearer VoIP Bearer

H.248

MAP

LTE

PSTN/ PLMN

Serving-GW

RA41336EN50GLA1

PDN-GW


Other IMS Network

SRVCC to WCDMA without PS HO UE

Source eNB

Source MME

SGW PGW

MSC MGW

Target MSC

Target SGSN

Target RNS

IMS SCC AS

Ongoing VoIP Session with IMS established over LTE Measurement Report

HO Required (S1) Bearer Spliting

PS to CS Request (Sv)

Prep HO Req HO Request (Iu CS) HO Ack (Iu CS) Prep HO Rsp Establish Circuit HO from EUTRAN HO Command (S1) Command

Initiation of Session Transfer (STN-SR)

PS to CS Response (Sv)

UE Tuning and HO Detection with new network SES [HO Complete]

HO Complete (Iu CS)

Answer PS to CS Complete/ACK (Sv) Delete Bearer [QCI1] (S11)

Routing Area Update

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Session Transfer Update remote end, Release Source IMS Access leg

SRVCC to WCDMA with PS HO UE

Source eNB

Source MME

SGW PGW

MSC MGW

Target MSC

Target SGSN

Target RNS

IMS SCC AS

Ongoing OngoingVoIP VoIPSession Session with with IMS IMS established establishedover overLTE LTE Measurement Report



Prep HO Req

Reloc/HO Request (Iu CS)

Forward Relocation Request (Gn/S3)

Reloc/HO Request/ACK (Iu PS)

Forward Relocation Response (Gn/S3) Reloc/HO Ack (Iu CS)

Prep HO Rsp Establish Circuit HO from EUTRAN HO Command (S1) Command



UE Tuning and HO Detection with new network SES [HO Complete] PS to CS Complete/ACK (Sv)

Reloc/HO Complete (Iu CS)

Answer

Delete Bearer [QCI1] (S11)

Reloc/HO Complete (Iu PS)

Forward Relocation Complete/Ack (Gn/S3) Update Bearer [NonGBR] (Gn/S4)

Release Resources (S1)

81

Delete Session (S11)

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SRVCC to GSM without DTM UE

Source eNB

Source MME

SGW PGW

MSC MGW

Target MSC

Target SGSN

Target RNS BSS

IMS SCC AS




Prep HO Req

HO Request (Iu CS) HO Ack (Iu CS)

Prep HO Rsp Establish Circuit HO from EUTRAN HO Command (S1) Command



UE Tuning and HO Detection with new network Suspend (see TS 23.060) Suspend Request/Response

SES [HO Complete]

Suspend

HO Complete (Iu CS)

Answer

PS to CS Complete/ACK (Sv) Bearer handling and suspension (S11)

CS Call ended -TAU

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SRVCC to GSM with DTM without PS HO UE

Source eNB

Source MME

SGW PGW

MSC MGW

Target MSC

Target SGSN

Target RNS BSS

IMS SCC AS




Prep HO Req HO Request (Iu CS) HO Ack (Iu CS) Prep HO Rsp Establish Circuit HO from EUTRAN HO Command (S1) Command



UE Tuning and HO Detection with new network SES [HO Complete]

HO Complete (Iu CS)

Answer PS to CS Complete/ACK (Sv) Delete Bearer [QCI1] (S11)

Routing Area Update

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SRVCC to WCDMA Counter Summary M8016C31

M8016C29



M8016C30

 HO attempts to UTRAN with SRVCC 84

Successful / Failed HO completions to UTRAN with SRVCC

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SRVCC to WCDMA Handover KPIs LTE_5564a Inter RAT HO to UTRAN with SRVCC Success Ratio

This KPI describes the inter RAT HO to UTRAN with SRVCC Success Ratio when the source eNB receives information that the UE successfully is connected to the target cell (UTRAN).

Logical formula Inter RAT HO UTRAN SRVCC SR =(number of successful inter RAT Hos UTRAN SRVCC) / (number of inter RAT HO attempts UTRAN SRVCC)*100%

85



100*sum([M8016C30]) / sum([M8016C29])

100*sum([ISYS_HO_UTRAN_SRVCC_SUCC]) / sum([ISYS_HO_UTRAN_SRVCC_ATT])

RA41336EN50GLA1


SRVCC to WCDMA Handover KPIs LTE_5563a Inter RAT HO to UTRAN with SRVCC Failure Ratio

This KPI describes the ratio of failed inter RAT handovers to UTRAN with SRVCC related to all attempted inter RAT handovers to UTRAN with SRVCC. This KPI represents the case of a failed Handover when all UE resources are still allocated for the UE.

Logical formula Inter RAT HO UTRAN SRVCC FR =(number of unsuccessful inter RAT Hos UTRAN SRVCC) /(number of inter RAT HO attempts UTRAN SRVCC)*100%

86



100*sum([M8016C31]) / sum([M8016C29])

100*sum([ISYS_HO_UTRAN_SRVCC_FAIL]) / sum([ISYS_HO_UTRAN_SRVCC_ATT])

RA41336EN50GLA1


SRVCC to GERAN Counter Summary M8016C3

M8016C33



M8016C34

 HO attempts to GERAN with SRVCC 87

Successful / Failed HO completions to GERAN with SRVCC

RA41336EN50GLA1


SRVCC to GERAN Handover KPIs LTE_5567a Inter RAT HO to GERAN with SRVCC Success Ratio This KPI describes the inter RAT HO to GERAN with SRVCC Success Ratio when the source eNB receives information that the UE successfully is connected to the target cell (GERAN).

Logical formula Inter RAT HO GERAN SRVCC SR =(number of successful inter RAT HOs GERAN SRVCC) /(number of inter RAT HO attempts GERAN SRVCC)*100%

88



100*sum([M8016C34]) / sum([ M8016C33])

100*sum([ISYS_HO_GERAN_SRVCC_SUCC]) / sum([ISYS_HO_GERAN_SRVCC_ATT])

RA41336EN50GLA1


SRVCC to GERAN Handover KPIs LTE_5566a Inter RAT HO to GERAN with SRVCC Failure Ratio

This KPI describes the ratio of failed inter RAT handovers to GERAN with SRVCC related to all attempted inter RAT handovers to GERAN with SRVCC. This KPI represents the case of a failed Handover when all UE resources are still allocated for the UE.

Logical formula Inter RAT HO GERAN SRVCC FR =(number of unsuccessful inter RAT HOs GERAN SRVCC) / (number of inter RAT HO attempts GERAN SRVCC)*100%

89



100*sum([M8016C35]) / sum([ M8016C33])

100*sum([ISYS_HO_GERAN_SRVCC_FAIL]) / sum([ISYS_HO_GERAN_SRVCC_ATT])

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Contents 1. LTE Handover Mobility Architecture 2. 3. 4. 5. 6. 7. 8. 9. 10.

90

Intra eNodeB Handover Inter eNodeB Handover via X2 interface Inter eNodeB Handover via S1 interface Intra-LTE Inter-Frequency Handover Inter-eNB Inter-Frequency Load Balancing Inter-System Mobility SRVCC to WCDMA and GSM X2 Interface Measurements Open Access Home eNB Mobility

RA41336EN50GLA1


X2 Interface (E)-RRC

User PDUs

.. User PDUs

PDCP RLC

TS 36.300

MAC

eNB

LTE-L1 (FDD/TDD-OFDMA/SC-FDMA)

• Inter eNodeB interface

LTE-Uu

X2-CP (Control Plane) TS 36.423 TS 36.422 TS 36.421

• X2AP special signalling protocol

X2-UP (User Plane)

• Functionalities – Facilitate inter eNodeB handover and provide

User PDUs

X2-AP

GTP-U

SCTP

UDP

IP

IP

L1/L2

L1/L2

data forwarding for it

X2 TS 36.424

TS 36.421

– Provide e.g. load information to neighbouring eNBs to facilitate radio resource and interference management

• Logical interface – Does not need direct site-to-site connection – Can be routed e.g. via core network as well

TS 36.420

eNB 91

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X2 Throughput Counters and KPIs E-UTRAN average incoming Signaling Throughput on X2

Shows the average incoming signaling throughput on X2AP layer per eNB Unit is Kbit/s M8004 Transport Load Measurements

Logical formula AVG IN X2 SIG THP = (incoming X2AP signaling volume) * 8 / (MEASUREMENT_DURATION * 60)



Sum ([M8004C0]) * 8 / (sum (MEASUREMENT_DU RATION) * 60)

Sum ([VOLUME_X2_IN_SIG_DATA]) * 8 / (sum (MEASUREMENT_DURATION) * 60)

M8004C0 Incoming signaling data volume in KByte

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X2 Throughput Counters and KPIs E-UTRAN average outgoing Signaling Throughput on X2

Shows the average outgoing signaling throughput on X2AP layer per eNB Unit is Kbit/s

Logical formula AVG OUT X2 SIG THP = (outgoing X2AP signaling volume) * 8 / (MEASUREMENT_DURATION * 60)



Sum ([M8004C1]) * 8 / (sum (MEASUREMENT_DU RATION) * 60)

Sum ([VOLUME_X2_OUT_SIG_DATA]) * 8 / (sum (MEASUREMENT_DURATION) * 60)

M8004C1 Outgoing signaling data volume in KByte

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X2 Throughput Counters and KPIs E-UTRAN average incoming Data Throughput on X2

Shows the average incoming user plane data throughput on X2AP layer per eNB Unit is Kbit/s

Logical formula



AVG X2 DAT THP IN = (incoming X2AP user plane data volume) * 8 / 1000 / (MEASUREMENT_DURATION * 60)

Sum ([M8004C2]) * 8 / 1000 / (sum (MEASUREMENT_DU RATION) * 60)

Sum ([X2_DATA_VOL_IN_UPLANE]) * 8 / 1000 / (sum (MEASUREMENT_DURATION) * 60)

M8004C2 Incoming user plane data volume in Byte

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X2 Throughput Counters and KPIs E-UTRAN average outgoing Data Throughput on X2

Shows the average outgoing user plane data throughput on X2AP layer per eNB Unit is Kbit/s

Logical formula



AVG X2 DAT THP OUT= (outgoing X2AP user plane data volume) * 8 / 1000 / (MEASUREMENT_DURATION * 60)

Sum ([M8004C3]) * 8 / 1000 / (sum (MEASUREMENT_DU RATION) * 60)

Sum ([X2_DATA_VOL_OUT_UPLANE]) * 8 / 1000 / (sum (MEASUREMENT_DURATION) * 60)

M8004C3 Outgoing user plane data volume in Byte

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Contents 1. LTE Handover Mobility Architecture 2. 3. 4. 5. 6. 7. 8. 9. 10.

96

Intra eNodeB Handover Inter eNodeB Handover via X2 interface Inter eNodeB Handover via S1 interface Intra-LTE Inter-Frequency Handover Inter-eNB Inter-Frequency Load Balancing Inter-System Mobility SRVCC to WCDMA and GSM X2 Interface Measurements Open Access Home eNB Mobility

RA41336EN50GLA1


LTE1442 Open Access Home eNB Mobility RL50 • HeNB is consumer or enterprise deployed eNodeB with low transmit power (~23 dBm) • Home eNodeB are distinguished by as configurable range of PCI • RRC connection release with redirect is used instead of prepared HO

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LTE1442 is the macro cell feature

Foreign vendor Home eNodeB's


LTE1442 Open Access Home eNB Mobility RL50 • Radio Network Layer Cause (Inter-RAT Redirection) is used to handover the UE to the Home eNB • After the redirect UE performs cell selection and call setup towards Home eNodeB

UE

Source eNB User Data

S-GW

User Data

RRC:Measurement Report (measResult(measId of „Event E-UTRA A3” or „Event E-UTRA A5”))

Decision for mobility towards a PCI belonging to Home eNB

M8008C15 UE Context Release with Redirect

other already existing PM counters for monitoring the redirect procedure are also applicable for the Redirect to Home eNB

98

MME

Home eNB

Number of UEs attempted to redirect to Home eNB

UE performs cell selection and call setup towards Home eNodeB

User Data

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User Data


Thank You !

RA41336EN50GLA1


06_RA41336EN50GLA1_LTE Mobility Connected Mode

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